In a vehicle comprising a transaxle which is powered by an engine through a transmission shaft and drives vehicle drive wheels to rotate, the transaxle is subjected to a reaction torque which is caused by the ground reacting against the rotation of the drive wheels. Such reaction torque tends to rotationally displace the transaxle about the axles of drive wheels so that portions of the vehicle body frame at which the transaxle is attached to the frame tend to be deformed to result in an inclined posture of the transaxle. In case where such inclined posture of transaxle is caused in a vehicle having a shaft-jointing structure where a universal joint is employed only between the transmission shaft set forth above and either of an engine output shaft or an input shaft of the transaxle, or in a vehicle having a shaft-jointing structure where the transmission shaft for connecting the engine output shaft and transaxle input shaft is jointed to both of these shafts using rubber joints, variation in angular velocity is caused at the joint or joints so that an unstable condition of rotational speed of the transaxle input shaft is caused whereby a variation in the travelling speed of vehicle is resulted.
As shown, for example, in JP, U No.61-127026, one of the conventional structures for avoiding such disadvantage is that a transaxle is fixedly secured to a vehicle body frame using a plurality of bolts extending in plural directions, namely lateral, vertical and logitudinal directions of a vehicle, so as to provide a support structure rigid enough to prevent the transaxle from being changed in posture. As shown, for example, in JP, U No.63-26440, another structure according to the prior art, is that two universal joints are employed so that no problem in power transmission from an engine to a transaxle may be caused even when the transaxle is changed in its posture. When the latter structure is employed, a transaxle is, in general, fixedly attached at its left and right axle casings to left and right frame members of a vehicle body frame.
Of the two prior art structures set forth above, the former one of providing a rigid support structure for the transaxle requires a lot of tapping operations, bolts, and assembling operations so that it is expensive. The latter structure of employing two universal joints is still expensive due to the use of two universal joints of a relatively large cost and may cause, when the posture of transaxle is varied, deviation in timing or unsmoothness with regard to the operation of a control mechanism for a speed change gearing or the like provided in the transaxle.
Accordingly, a primary object of the present invention is to provide an improved transaxle-supporting structure which eliminates these problems of the prior art structures.